1. Field of the Invention
The present invention relates generally to oral/enteral syringe packaging equipment and more specifically to a partially automated system for preparing patient-specific doses of selected pharmaceutical liquid medication for administration by oral/enteral syringe on a just-in-time basis, for use in a hospital pharmacy.
2. Description of the Background
Enteral syringes are used for tube feeding, irrigation or drug administration into the gastrointestinal (GI) tract. This contrasts with parenteral nutrition or drug administration which occurs from routes outside the GI tract, such as intravenous routes. Oral syringes are used to administer liquid medicine into the mouth, as an alternative to pills which can present a choking hazard or be expectorated, typically for infants/children and uncooperative or geriatric adults. The oral syringe directs liquid medicine to the back of the throat prompting a swallowing response. Parenteral syringes (e.g., injectable syringes) on the other band, are used to administer medication into the body by injecting its contents through the skin. Injectable syringes utilize a needle on the tip of the syringe. Injectable syringes must he manufactured and packaged in a sterile environment.
Research has shown that the potential for adverse drug events within the pediatric inpatient population is about three times as high as among hospitalized adults. See, Joint Commission, Preventing Pediatric Medication Errors, Issue 39 (2008). According to the Commission Report, the most common types of harmful pediatric medication errors were improper dose/quantity (37.5 percent) and unauthorized/wrong drug (13.7 percent), followed by improper preparation or dosage form. Enteral/oral syringes help to minimize these problems and are considered the gold standard for delivering medicine to children.
Enteral/oral syringes are comprised of a simple piston pump with a plunger that fits tightly in one end of a cylindrical tube (the barrel) and can be pushed or pulled along inside the barrel to create negative or positive relative pressure within the barrel that causes the syringe to take in or expel a liquid or gas through an orifice (terminal discharge) at the opposing end of the barrel. The barrel of an enteral/oral syringe is typically made of plastic and is at least partially transparent along its length with graduated markings to indicate the volume of fluid in the syringe based on the position of the plunger visible within the barrel. Enteral/oral syringes come in a wide range of sixes and with some variation in configuration. For example, some enteral/oral syringes have the terminal discharge located along the central axis while others have the terminal discharge offset from the central axis. This variability makes it difficult to automate the filling process. Enteral/oral syringes are commonly marked in units of milliliters and come in standard sizes ranging from 0.5 to 60 milliliters. An annular flange partially or fully encircling the outside surface of the barrel is typically provided to facilitate compression of the plunger into the barrel. The plunger is also typically plastic as this provides a good seal within the barrel and is inexpensive to produce so as to be disposable, reducing the risk of contamination or transmission of communicable disease.
Pharmacies at in-patient medical facilities and other medical institutions fill a large number of prescriptions on a daily basis including prescriptions for liquid or compounded suspension medicines to be administered by oral/enteral syringe, and must do so accurately for medical safety reasons. For example, the volume of an oral/enteral pediatric prescription's dose is determined by the child's weight. This makes it impractical to stock pre-filled syringes due to the wide range of fill volumes required. As a result, pediatric enteral/oral liquid doses are prepared in the hospital pharmacy on a patient-specific, just-in-time basis. The process of filling numerous, variously sized single dose prescriptions for delivery by oral/enteral syringe is time consuming, labor intensive and prone to human error. To insure that the medication, is packaged error-free, the pharmacy technician must make sure that: (1) the syringe contains the correct medication; (2) the syringe contains the correct amount of medication; (3) the syringe is capped correctly; (4) the medication has not expired; (5) the medication has not been recalled; (6) the medication, when required, is shaken; (7) the medication, when required, has been properly refrigerated; (8) the medication, when required, has been properly protected from exposure to light; (9) the information on the syringe label is correct; (10) the syringe is placed into the correct bag; (11) the information on the bag containing the syringe is correct; (12) the bag is properly sealed; and (13) the syringe is protected from cross contamination from other medications. The process typically requires a pharmacist or pharmacy technician to retrieve the correct medication from a storage cabinet (with or without light protection) or refrigerated storage area. The liquid medications are typically stored in a container sealed with, a safety cap or seal. After confirming the contents of the retrieved container and shaking the medication (if necessary), the technician manually opens the cap and attaches the tip of an enteral/oral syringe to the container, withdrawing the plunger to draw the medication into the barrel of the syringe. After filling with a proper amount, the tip of the syringe is covered with a cap for transport to the patient and the syringe is labeled to indicate its content, the intended recipient, and then bagged. Prior to administering the dose, the nurse can determine the amount of the dose by observing where the tip of the plunger or piston is located in the barrel. Oral/enteral syringes are relatively inexpensive and disposable.
Currently, the degree of automation in the hospital pharmacy for the packaging of oral/enteral syringes is very limited. Islands of automation exist, such as automatic labeling of the syringe and bagging of the filled and capped syringe. However, the filling and capping are done manually. Scanners, cameras, bar code readers and track-and-trace technology have not been applied on an integrated, comprehensive basis for the packaging of enteral/oral syringes in the hospital pharmacy. The potential to reduce medication errors using this technology is significant yet largely untapped. Automated systems have been developed by Baxa, Inc., For Health Technologies, Inc., Intelligent Hospital Systems and others for the automated filling of injectable syringes.
For example, U.S. Pat. Nos. 6,991,002; 7,017,622; 7,631,475 and 6,976,349 are all drawn to automated removal of a tip cap from an empty syringe, placing the tip cap at a remote location, and replacing the tip cap on a filled syringe. U.S. Pat. Nos. 7,117,902 and 7,240,699 are drawn to automated transfer of a drug vial from storage to a fill station. U.S. Pat. No. 5,884,457 shows a method and apparatus for filling syringes using a pump connected by hose to a fluid source. U.S. Pat. No. 7,610,115 and Application. 20100017031 show an Automated Pharmacy Admixture System (APAS). U.S. Application 20090067973 shows a gripper device for handling syringes of different diameters with tapered or angled gripper fingers. U.S. Pat. No. 7,343,943 shows a medication dose under-fill detection system. U.S. Pat. No. 7,260,447 shows an automated system for fulfilling pharmaceutical prescriptions. U.S. Pat. No. 7,681,606 shows an automated system and process for filing syringes of multiple sizes. U.S. Pat. No. 6,877,530 shows an automated means for withdrawing a syringe plunger. U.S. Pat. No. 5,692,640 shows a system for establishing and maintaining the identity of medication in a vial using preprinted, pressure sensitive, syringe labels.
The foregoing references are for packaging injectable syringes. The packaging process required for injectable syringes is significantly different than that for enteral/oral syringes. Injectable syringes must be packaged in a sterile environment as the medication is injected into the body. This requirement adds cost and complexity to the machine. Injectable medications, when packaged on a just-in-time basis as with the Baxa. For Health Technologies, and Intelligent Hospital. System machines, must typically be prepared by the machine before the medication is filled into the syringe. The medication preparation process involves diluting the medication or reconstituting the medication from a powdered state with water. This process adds expense and slows down the packaging process as well. The Intelligent Hospital Systems syringe packaging system is designed to be used to package cytotoxic medications which are hazardous. To avoid harm to the operator, this machine uses a robot located within an isolating barrier at considerable cost. The Baxa, For Health Technologies, and Intelligent Hospital System machines require the use of expensive disposable product contact parts when a different medication is to be filled. The foregoing machines are not suitable for packaging enteral/oral syringes due to their capital cost, complexity, slow production rates, inability to handle enteral/oral medication containers, and the requirement of expensive disposable contact parts. Consequently, existing automation does not address the needs of medical institutions desiring an affordable pharmacy automation system for patient safety, prescription tracking and improved productivity. The present invention was developed to fill this void.
Oral and/or enteral syringes are manufactured in a variety of sizes with differing tip and plunger configurations. Moreover, oral/enteral medications are commonly provided in bulk form in variously sized bottles or containers having threaded screw caps that must be removed and replaced between uses. Additionally, in-patient medical facilities such as hospitals are moving toward electronic prescription (“e-prescription”) systems which use computer systems to create, modify, review, and/or transmit medication prescriptions from the healthcare provider to the pharmacy. Handwritten and facsimile prescriptions are often very difficult to read, and decimal places are sometimes misinterpreted. While e-prescribing improves patient safety and saves money by eliminating the inefficiencies and inaccuracies of the manual, handwritten prescription process, any syringe fill automation, system suitable for use in a hospital setting must interface with an existing e-prescription system (which records and transmits prescriptions to the pharmacy), and must he capable of filling prescription orders in a just-in-time environment.
Given the diversity of enteral/oral syringes and medicines available, any semi-automated (or fully-automated) system will need sufficient dexterity to manipulate all the myriad prescription bottles containing the pharmaceuticals to be dispensed as well as variously sized enteral/oral syringes, bringing them together in a controlled environment to quickly and accurately fill and label each syringe and to verify its work as it proceeds in order to avoid errors in the process. Such a system would need to be reliably constructed so as to minimize downtime, quickly take and fill orders, be easy to clean and capable of maintaining an environment free from cross contamination. Such a system would also need to be able to interact with a human operator at multiple points in the operation.
The present inventors herein provide a semi-automated system suitable for use in a hospital setting for filling patient-specific doses of liquid medications to be administered by oral/enteral syringes on a just-in-time basis, as well as an automated alternative. The system enables hospital pharmacists to simplify and streamline their task, increasing the number of prescriptions that can be filled in a day, improving patient safety and care by minimizing medication errors and the consequences that ensue.